World tennis has been rocked by allegations that the sport's governing authorities failed to deal with widespread match fixing tied to gambling syndicates in Russia, northern Italy, and Sicily.

The findings were reported by the BBC and the online BuzzFeed News, which said they obtained the findings of an investigation set up in 2007 by the Association of Tennis Professionals (ATP), the governing body of men's professional tennis.

The BBC and BuzzFeed News reports said 16 players ranked in the world's top 50 were repeatedly flagged in reports to the governing authorities' Tennis Integrity Unit (TIU) over suspicions they threw matches.

The reports said the TIU, set up to police illegal activities in tennis, either failed to act on information about suspicious behavior or failed to impose any sanctions.

The BBC said Russian, Italian, and Sicilian betting syndicates made hundreds of thousands of dollars on games thought to have been fixed, including three at Wimbledon.